
def nest1():
    for num1 in range(1,10):
        for num2 in range(1,10):
            print(f"{num2}*{num1}={num2*num1}".ljust(6),end=" ")
        print()

def nest2():
    """
      打印上三角型的九九乘法表
    """
    for num1 in range(1,10):
        for num2 in range(num1,10):
            print(f"{num1}*{num2}={num2*num1}".ljust(6),end=" ")
        print()

def nest3():
    """
      打印下三角型的九九乘法表
    """
    for num1 in range(1,10):
        for num2 in range(1,num1+1):
            print(f"{num1}*{num2}={num2*num1}".ljust(6),end=" ")
        print()
# 调用
nest3()